Apparatus for the distribution of liquid on the upright walls of pipe exchangers



Apnl 20, 1965 E. SCHOLZ 3,179,126

APPARATUS FOR THE DISTRIBUTION OF LIQUID ON THE UPRIGHT WALLS OF PIPE EXCHANGERS Filed Oct. 4, 1962 2 Sheets-Sheet 1 INVENTOR.

E RICH SCHOLZ ATTORNEYS 2 Sheets-Sheet 2 E. scHoLz ORIGINAL 7'00 LARGE CROSS-SECTION OF THE INSEPTED SLEEVE THE UPRIGHT WALLS OF PIPE EXCHANGERS APPARATUS FOR THE DISTRIBUTION OF LIQUID ON Filed Oct. 4, 1962 A ril 20, 1965 FIG. 3

MO ZQRQMW wmdtu INVENTOR. EP/CH SCHOLZ A TTORNEYS FIG. 4

United States Patent 3,179,126 APPARATUS FOR THE DISTREUTION 0F LIQUID ON THE UPRIGHT WALLS 0F PEPE EXCHANGERS Erich Scholz, Cologne-Rich], Germany, assignor to Farbeufahriken Bayer Aktiengesellschaft, Leverkusen, Germany, a corporation of Germany Filed Oct. 4, 1962, Ser. No. 228,474 Claims priority, application Germany, Oct. 7, 1961, F 35,079 6 Claims. (Cl. 138-38) This application is a continuation-in-part application of U.S. application Serial No. 98,931, filed March 28, 1961, now abandoned.

The invention relates to apparatus for distributing the liquid on the upright walls of tubular exchangers as may be used for heat exchange between materials on opposite sides of the tubes and/or as falling film evaporators or fractionators, which apparatus consists of perforated sleeves which are pushed on to the tube ends above the upper tube plate. With the known pushon sleeves of this type, which are for example formed with tangential slots, the quantity of liquid entering the tube is approximately proportional to the power of 1.5 of the effective liquid level. With an inclined position of the tube plate, the liquid is thus distributed differently over the internal circumference of the tube, so that the latter is only partially wetted. This disadvantage occurs to an increased extent with trickling densities of less than 0.3 m. of liquid per hour and per metre of tube periphery. In operation, deflections from the vertical can scarcely be avoided, even with careful mounting, because of adjacent loads or thermal expansion of the connecting pipes.

It has now been found that this disadvantage is obviated and a uniform distribution of the liquid, and thus a uniform film flow over the inner circumference of the tube, is obtained even with small trickling densities, if, according to the invention, insertable sleeves extending into the tubes are provided in addition to the push-on sleeves, the said insertable sleeves being formed externally with at least one helical channel, the outer edges of which fit tightly on the inside wall of the tube.

The helical channel can be formed as a multiple thread. The channels can be arranged on sections on the insertable sleeve and be disposed vertically spaced from one another. It is advantageous if, in accordance with the invention, the axial depths of the channels from section to section increase downwardly. The openings from the multiple channels can be olfset at an angle to one another. The axial depth of the uppermost channel section on the insertable sleeve is so chosen that the flow resistance causes the setting of a defined liquid level over this channel section. The through fiow through the uppermost channel section then follows the law of flow with a tube filled by liquid and is approximately proportional to the root of the effective level. Differences in the effective level, which are caused by an inclined position of the tube plate, consequently do not produce any appreciable diiference in the quantity supplied per tube, that is to say, of the quantities being distributed from the plate on to the separate tubes. The flow in the passage of the next lower channel section, the axial depth of which is greater than that of the section above it, is that of an open trough, which is not completely filled owing to the greater depth of the cross-section. The reduced Wall friction leads in this channel section to a desired increase in speed tangentially of the tube wall. On discharging at the openings from the multiple channels, which are disposed at an angle to one another, a closed film flow is produced over the periphery of the tube wall, even with extremely small trickling densities.

In some cases, for example in absorption processes Patented Apr. 20, 1965 or when an aerosol is converted from the gaseous to the liquid phase, it is advantageous for the liquid to have a pulsating flow at the time when it leaves the helical grooves.

This may be achieved in accordance with the invention by constructing the grooves so that they have a periodically varying cross-section. In practice, this may be achieved by the fact that a screw thread which is originally of too large a diameter is turned eccentrically on a lathe to the dimension of the internal diameter of the pipe. This results in flow paths with periodically varying cross-section and corresponding accelerations or retardations of the fiow.

One constructional example of the invention is shown diagrammatically in the drawing, in which:

FIG. 1 is an elevationview in cross-section of a portion of an upper tube plate provided with a distributor according to the invention;

FIG. 2 is a crosssectional View of the distributor taken on line 22 in FIG. 1;

FIG. 2a is a schematic representation of a preferred construction;

FIG. 3 is a view corresponding to that shown in FIG. 2, but for a construction wherein the threads are eccentrically disposed in the tube; and

FIG. 4 is a graph for an eccentric construction as is shown in FIG. 3, of groove cross-sectional area versus circumferential position.

A sleeve 3 is pushed on to the tube 2 which is arranged in the plate l and the internal periphery of which is to be uniformly wetted, the said sleeve being formed with holes iwhich are covered with a mesh screen 5 for retaining solid substances.

Inserted into the push-on sleeve 3 is a second sleeve 6 which rests with its flanged rim 7 onthe upper rimof the sleeve 3 and the lower portion of which projects into the tube 2. The insertable sleeve 6 is formed externally of its lower portion with helical channels 8 and 9, each of which forms a channel section spaced from the other. Each channel is constructed as a triple thread. The section of the thread 8 is ofiiset by 30 relatively to that of the thread 9. Thus, as is represented schematically in FIG. 2a, if the circumferential position of the outlets of the channels in upper section ii are at locations indicated by 12, l3, and 14, the inlets to the channels of the lower section 9 are at locations 12, 13, and 14, which are disposed, respectively, in a projection in plan as is shown in FIG. 2a, at 30 to locations l2, l3, and 14'. Each channel section has three tangential openings l2, 13, 14 (FIG. 2) offset by The depth of the passage 10 of the upper thread section 8 is smaller than the depth of the passage 11 of the lower thread section 9. The position of the tangential openings of the triple threads is marked on the knurled rim '7 of the insertable sleeve 6, so that with an inclined position of the tubes, two openings can be turned in order to balance the over-hanging side.

In the embodiment shown in FIG. 3, the lower threads 9 are eccentrical. This construction can be provided by machining a thread section of the diameter indicated by the dotted line to provide the eccentric design in a thread section having a diameter of the inside of the tube 2. The inlets of the triple thread courses 15, 16, 17 are offset by 120. The outlets of the triple thread courses are, of course likewise, offset by 120, but they may be offset at any angle with respect to the inlets depending on the pitch and length of the thread.

FIG. 4 is a graph showing the periodic relationship between the cross-section of the groove and the flow of liquid, and indicates the construction which provides the pulsating flow.

I claim:

1. Apparatus for distributing liquid over the surface of an up'rig t tube for fiow down over the surface of the tube comprising an upright tube, a tube sheet receiving the upper end :portion of said tube, and for maintaining a reservoir of liquid for supply to the tube, a sleeve for the tube disposed at the upper end portion thereof and providing an annulus between the tube and sleeve, means defining a helical thread course in said annulus, said thread course providing a helical liquid flow course through the annulus commencing in an inlet to the course and terminating in an outlet disposed below said inlet for discharging liquid traversing said flow course on the tube surface, the cross-sectional area of the helical flow course increasing in the direction of liquid flow from the said inlet to said outlet, and means for communicating liquid maintained over said tube sheet with said helical flow course inlet.

2. Apparatus according to claim 1, including multiple threads as aforesaid, the inlets of said threads being circumferentially offset and the outlets thereof being circuniferentially offset.

3. Apparatus according to claim 2, said thread courses being divided into axially spaced thread sections, the thread depth increasing from section to section in the downward direction.

4. Apparatus according to claim 3, the threaded sections being circunrferentially offset with respect to, each other.

5. Apparatus according to claim 2, said sleeve being turnable in said tube, whereby the circumferential position of the helical course inlets can be adjusted to accommodate the apparatus to inclination of the tubes from the vertical. 7

6. Apparatus according to claim 1, said cross-sectional area of the helical flow course has a periodically varying ci'osseeotion. 7

References Cited by the Examiner UNITED STATES PATENTS 328,069 8/06 Schwager 165-418 993,831 5/11 Junggren 13842 XR 1,557,838 16/25 Hiller 138-38 1,776,483 9/30 White 165-118 2,023,630 12/35 Leluge 165-ll9 XR 2,318,205 5/43 Eisenlohr 13842 XR FOREIGN PATENTS 33,534 11/21 Norway.

EDWARD V. BENT-1AM, Primary Examiner. 

1. APPARATUS FOR DISTRIBUTING LIQUID OVER THE SURFACE OF AN UPRIGHT TUBE FOR FLOW DOWN OVER THE SURFACE OF THE TUBE COMPRISING AN UPRIGHT TUBE, A TUBE SHEET RECEIVING THE UPPER END PORTION OF SAID TUBE, AND FOR MAINTAINING A RESERVOIR OF LIQUID FOR SUPPLY TO THE TUBE, A SLEEVE FOR THE TUBE DISPOSED AT THE UPPER END PORTION THEREOF AND PROVIDING AN ANNULUS BETWEEN THE TUBE AND SLEEVE, MEANS DEFINING A HELICAL THREAD COURSE IN SAID ANNULUS, SAID THREAD COURSE PROVIDING A HELICAL LIQUID FLOW COURSE THROUGH THE ANNULUS COMMENCING IN AN INLET TO THE COURSE AND TERMINATING IN AN OUTLET DISPOSED BELOW SAID INLET FOR DISCHARGING LIQUID TRAVERSING SAID FLOW COURSE ON 